Modulating the immune response to SARS-CoV-2 by different nanocarriers delivering an mRNA expressing trimeric RBD of the spike protein: COVARNA Consortium.

Vaccines based on mRNA technology have revolutionized the field. In fact, lipid nanoparticles (LNP) formulated with mRNA are the preferential vaccine platform used in the fight against SARS-CoV-2 infection, with wider application against other diseases. The high demand and property right protection of the most potent cationic/ionizable lipids used for LNP formulation of COVID-19 mRNA vaccines have promoted the design of alternative nanocarriers for nucleic acid delivery. In this study we have evaluated the immunogenicity and efficacy of different rationally designed lipid and polymeric-based nanoparticle prototypes against SARS-CoV-2 infection. An mRNA coding for a trimeric soluble form of the receptor binding domain (RBD) of the spike (S) protein from SARS-CoV-2 was encapsulated using different components to form nanoemulsions (NE), nanocapsules (NC) and lipid nanoparticles (LNP). The toxicity and biological activity of these prototypes were evaluated in cultured cells after transfection and in mice following homologous prime/boost immunization. Our findings reveal good levels of RBD protein expression with most of the formulations. In C57BL/6 mice immunized intramuscularly with two doses of formulated RBD-mRNA, the modified lipid nanoparticle (mLNP) and the classical lipid nanoparticle (LNP-1) were the most effective delivery nanocarriers at inducing binding and neutralizing antibodies against SARS-CoV-2. Both prototypes fully protected susceptible K18-hACE2 transgenic mice from morbidity and mortality following a SARS-CoV-2 challenge. These results highlight that modulation of mRNAs immunogenicity can be achieved by using alternative nanocarriers and support further assessment of mLNP and LNP-1 prototypes as delivery vehicles for mRNA vaccines.

Safety and immunogenicity of a recombinant protein RBD fusion heterodimer vaccine against SARS-CoV-2.

In response to COVID-19 pandemic, we have launched a vaccine development program against SARS-CoV-2. Here we report the safety, tolerability, and immunogenicity of a recombinant protein RBD fusion heterodimeric vaccine against SARS-CoV-2 (PHH-1V) evaluated in a phase 1-2a dose-escalation, randomized clinical trial conducted in Catalonia, Spain. 30 young healthy adults were enrolled and received two intramuscular doses, 21 days apart of PHH-1V vaccine formulations [10 µg (n = 5), 20 µg (n = 10), 40 µg (n = 10)] or control [BNT162b2 (n = 5)]. Each PHH-1V group had one safety sentinel and the remaining participants were randomly assigned. The primary endpoint was solicited events within 7 days and unsolicited events within 28 days after each vaccination. Secondary endpoints were humoral and cellular immunogenicity against the variants of concern (VOCs) alpha, beta, delta and gamma. All formulations were safe and well tolerated, with tenderness and pain at the site of injection being the most frequently reported solicited events. Throughout the study, all participants reported having at least one mild to moderate unsolicited event. Two unrelated severe adverse events (AE) were reported and fully resolved. No AE of special interest was reported. Fourteen days after the second vaccine dose, all participants had a >4-fold change in total binding antibodies from baseline. PHH-1V induced robust humoral responses with neutralizing activities against all VOCs assessed (geometric mean fold rise at 35 days p < 0.0001). The specific T-cell response assessed by ELISpot was moderate. This initial evaluation has contributed significantly to the further development of PHH-1V, which is now included in the European vaccine portfolio.ClinicalTrials.gov Identifier NCT05007509EudraCT No. 2021-001411-82.

Safety and immunogenicity of the protein-based PHH-1V compared to BNT162b2 as a heterologous SARS-CoV-2 booster vaccine in adults vaccinated against COVID-19: a multicentre, randomised, double-blind, non-inferiority phase IIb trial.

Background: A SARS-CoV-2 protein-based heterodimer vaccine, PHH-1V, has been shown to be safe and well-tolerated in healthy young adults in a first-in-human, Phase I/IIa study dose-escalation trial. Here, we report the interim results of the Phase IIb HH-2, where the immunogenicity and safety of a heterologous booster with PHH-1V is assessed versus a homologous booster with BNT162b2 at 14, 28 and 98 days after vaccine administration. Methods: The HH-2 study is an ongoing multicentre, randomised, active-controlled, double-blind, non-inferiority Phase IIb trial, where participants 18 years or older who had received two doses of BNT162b2 were randomly assigned in a 2:1 ratio to receive a booster dose of vaccine-either heterologous (PHH-1V group) or homologous (BNT162b2 group)-in 10 centres in Spain. Eligible subjects were allocated to treatment stratified by age group (18-64 versus ≥65 years) with approximately 10% of the sample enrolled in the older age group. The primary endpoints were humoral immunogenicity measured by changes in levels of neutralizing antibodies (PBNA) against the ancestral Wuhan-Hu-1 strain after the PHH-1V or the BNT162b2 boost, and the safety and tolerability of PHH-1V as a boost. The secondary endpoints were to compare changes in levels of neutralizing antibodies against different variants of SARS-CoV-2 and the T-cell responses towards the SARS-CoV-2 spike glycoprotein peptides. The exploratory endpoint was to assess the number of subjects with SARS-CoV-2 infections ≥14 days after PHH-1V booster. This study is ongoing and is registered with ClinicalTrials.gov, NCT05142553. Findings: From 15 November 2021, 782 adults were randomly assigned to PHH-1V (n = 522) or BNT162b2 (n = 260) boost vaccine groups. The geometric mean titre (GMT) ratio of neutralizing antibodies on days 14, 28 and 98, shown as BNT162b2 active control versus PHH-1V, was, respectively, 1.68 (p < 0.0001), 1.31 (p = 0.0007) and 0.86 (p = 0.40) for the ancestral Wuhan-Hu-1 strain; 0.62 (p < 0.0001), 0.65 (p < 0.0001) and 0.56 (p = 0.003) for the Beta variant; 1.01 (p = 0.92), 0.88 (p = 0.11) and 0.52 (p = 0.0003) for the Delta variant; and 0.59 (p ≤ 0.0001), 0.66 (p < 0.0001) and 0.57 (p = 0.0028) for the Omicron BA.1 variant. Additionally, PHH-1V as a booster dose induced a significant increase of CD4+ and CD8+ T-cells expressing IFN-γ on day 14. There were 458 participants who experienced at least one adverse event (89.3%) in the PHH-1V and 238 (94.4%) in the BNT162b2 group. The most frequent adverse events were injection site pain (79.7% and 89.3%), fatigue (27.5% and 42.1%) and headache (31.2 and 40.1%) for the PHH-1V and the BNT162b2 groups, respectively. A total of 52 COVID-19 cases occurred from day 14 post-vaccination (10.14%) for the PHH-1V group and 30 (11.90%) for the BNT162b2 group (p = 0.45), and none of the subjects developed severe COVID-19. Interpretation: Our interim results from the Phase IIb HH-2 trial show that PHH-1V as a heterologous booster vaccine, when compared to BNT162b2, although it does not reach a non-inferior neutralizing antibody response against the Wuhan-Hu-1 strain at days 14 and 28 after vaccination, it does so at day 98. PHH-1V as a heterologous booster elicits a superior neutralizing antibody response against the previous circulating Beta and the currently circulating Omicron BA.1 SARS-CoV-2 variants in all time points assessed, and for the Delta variant on day 98 as well. Moreover, the PHH-1V boost also induces a strong and balanced T-cell response. Concerning the safety profile, subjects in the PHH-1V group report significantly fewer adverse events than those in the BNT162b2 group, most of mild intensity, and both vaccine groups present comparable COVID-19 breakthrough cases, none of them severe. Funding: HIPRA SCIENTIFIC, S.L.U.

The Combination of an mRNA Immunogen, a TLR7 Agonist and a PD1 Blocking Agent Enhances In-Vitro HIV T-Cell Immune Responses.

The development of new strategies to achieve a functional cure for HIV remains a priority. We tested a novel HIV therapeutic vaccine using unmodified mRNA (TMEP-B) and mRNA modified by 1-methyl-3'-pseudouridylyl (TMEP-Bmod) expressing both a multiepitopic sequences from Gag, Pol, and Nef proteins, including different CD4 and CD8 T-cell epitopes functionally associated with HIV control in transfected monocyte-derived dendritic cells (MDDCs) obtained from HIV infected patients. In vitro assays were used to test the mRNAs alone and in combination with immunomodulator agents, such as the TLR-7 agonist Vesatolimod and the PD-1 antagonist Nivolumab to try to improve HIV-specific cellular immune responses. Combining the mRNAs with the immunomodulators enhanced HIV-specific T-cell responses, together with the secretion of IFNγ, IP10, MIP-1α, and MIP-1ß, which are fundamental mediators of viral control. Our data suggest that the mRNA vaccine prototypes TMEP-B and TMEP-Bmod, when combined with Vesatolimod and/or Nivolumab, could achieve functional cure for patients with HIV.

Pharmacokinetics, the Immunological Impact, and the Effect on HIV Ex-Vivo Infectivity of Maraviroc, Raltegravir, and Lopinavir in Men Who Have Sex with Men Using Postexposure Prophylaxis.

Most of the studies using the colorectal tissue explants challenge model have been conducted after one single dose and before reaching a steady state. We consider that longer exposure as in 28-day postexposure prophylaxis (PEP) course and in an at-risk setting, such as after a sexual risk exposure to HIV could give us valuable information about these drugs. In a substudy we assessed pharmacokinetics, changes on immune system and ex-vivo rectal mucosal susceptibility to HIV-1 infection after taking maraviroc (MVC), raltegravir (RAL), and ritonavir-boosted lopinavir (LPV/r) PEP-based regimens in 30 men who have sex with men. Participants received 28 days of twice-daily MVC (n = 11), RAL (n = 10) or LPV/r (n = 9) all with tenofovir/emtricitabine (TDF/FTC) backbone. Blood, rectal fluid, and rectal tissue samples were collected at days 7, 28, and 90 after starting PEP. The samples obtained at day 90 were considered baseline. All studied antiretrovirals were quantifiable at 7 and 28 days in all tissues. Activation markers were increased in CD4 mucosal mononuclear cells (MMCs) after 28 days of MVC: CD38 + 68.5 versus 85.1, p = .008 and CD38+DR +16.1 versus 26.7, p = .008. Exposure to MVC at both endpoints (7 and 28 days) was associated with significant suppression of HIV-1BAL (p = .005 and p = .028), but we did not observe this effect with RAL or LPV/r. Merging together changes in MMC in all arms, we found a positive correlation in the CD8 T cell lineage between the infectivity at day 7 and activation (CD38+ r = 0.43, p = .025, DR + r = 0.547, p = .003 and 38+DR+ r = 0.526, p = .05), senescence (CD57+CD28- r = 0.479, p = .012), naive cells (RA+CCR7+ r = 0.484, p = .01), and CCR5 expression (r = 0.593, p = .001). We conclude that MVC in combination with TDF/FTC was associated with viral suppression in rectal explants and that overall ex-vivo HIV infectivity correlated with activation and senescence in CD8 MMCs.

Immunological and virological findings in a patient with exceptional post-treatment control: a case report.

BACKGROUND: Although antiretroviral therapy (ART) is effective in suppressing viral replication, HIV-1 persists in reservoirs and rebounds after ART has been stopped. However, a very few people (eg, elite and post-treatment controllers) are able to maintain viral loads below detection limits without ART, constituting a realistic model for long-term HIV remission. Here, we describe the HIV control mechanisms of an individual who showed exceptional post-treatment control for longer than 15 years. METHODS: We report the case of a Hispanic woman aged 59 years with sexually acquired acute HIV infection, who was included in an immune-mediated primary HIV infection trial involving a short course of ciclosporine A, interleukin-2, granulocyte macrophage colony-stimulating factor, and pegylated interferon alfa, followed by analytical treatment interruption. We did the following viral assays: total and integrated HIV-1 DNA in CD4 T cells and rectal tissue, quantitative viral outgrowth assay, HIV-1 infectivity in peripheral blood mononuclear cells and CD4 T-cell cultures and viral inhibitory activity by natural killer (NK) and CD8 T cells. NK and T-cell phenotypes were determined by flow cytometry. HLA, killer cell immunoglobulin-like receptors, Δ32CCR5, and NKG2C alleles were genotyped. FINDINGS: After ART and immunomodulatory treatment, the person maintained undetectable plasma viral load for 15 years. HIV-1 subtype was CFR_02AG, CCR5-tropic. We found progressive reductions in viral reservoir during the 15-year treatment interruption: total HIV DNA (from 4573·50 copies per 106 CD4 T cells to 95·33 copies per 106 CD4 T cells) and integrated DNA (from 85·37 copies per 106 CD4 T cells to 5·25 copies per 106 CD4 T cells). Viral inhibition assays showed strong inhibition of in vitro HIV replication in co-cultures of CD4 T cells with autologous NK or CD8 T cells at 1:2 ratio (75% and 62%, respectively). Co-cultures with NK and CD8 T cells resulted in 93% inhibition. We detected higher-than-reference levels of both NKG2C-memory-like NK cells (46·2%) and NKG2C γδ T cells (64·9%) associated with HIV-1 control. INTERPRETATION: We described long-term remission in a woman aged 59 years who was treated during primary HIV infection and has maintained undetectable viral load for 15 years without ART. Replication-competent HIV-1 was isolated. NKG2C-memory-like NK cells and γδ T cells were associated with the control viral replication. Strategies promoting these cells could bring about long-term HIV remission. FUNDING: Fondo Europeo para el Desarrollo Regional (FEDER), SPANISH AIDS Research Network (RIS), Fondo de Investigación Sanitaria (FIS), HIVACAT, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), CERCA Programme/Generalitat de Catalunya, la Caixa Foundation, and Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC). TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Assessment of Human SARS CoV-2-Specific T-Cell Responses Elicited In Vitro by New Computationally Designed mRNA Immunogens (COVARNA).

The COVID-19 pandemic has brought significant changes and advances in the field of vaccination, including the implementation and widespread use of encapsidated mRNA vaccines in general healthcare practice. Here, we present two new mRNAs expressing antigenic parts of the SARS-CoV-2 spike protein and provide data supporting their functionality. The first mRNA, called RBD-mRNA, encodes a trimeric form of the virus spike protein receptor binding domain (RBD). The other mRNA, termed T-mRNA, codes for the relevant HLA I and II spike epitopes. The two mRNAs (COVARNA mRNAs) were designed to be used for delivery to cells in combination, with the RBD-mRNA being the primary source of antigen and the T-mRNA working as an enhancer of immunogenicity by supporting CD4 and CD8 T-cell activation. This innovative approach substantially differs from other available mRNA vaccines, which are largely directed to antibody production by the entire spike protein. In this study, we first show that both mRNAs are functionally transfected into human antigen-presenting cells (APCs). We obtained peripheral blood mononuclear cell (PBMC) samples from three groups of voluntary donors differing in their immunity against SARS-CoV-2: non-infected (naïve), infected-recovered (convalescent), and vaccinated. Using an established method of co-culturing autologous human dendritic cells (hDCs) with T-cells, we detected proliferation and cytokine secretion, thus demonstrating the ability of the COVARNA mRNAs to activate T-cells in an antigen-specific way. Interestingly, important differences in the intensity of the response between the infected-recovered (convalescent) and vaccinated donors were observed, with the levels of T-cell proliferation and cytokine secretion (IFNγ, IL-2R, and IL-13) being higher in the vaccinated group. In summary, our data support the further study of these mRNAs as a combined approach for future use as a vaccine.

Effect of Intranodally Administered Dendritic Cell-Based HIV Vaccine in Combination With Pegylated Interferon α-2a on Viral Control Following ART Discontinuation: A Phase 2A Randomized Clinical Trial.

Introduction: Functional cure has been proposed as an alternative to lifelong antiretroviral therapy and therapeutic vaccines represent one of the most promising approaches. Materials and Methods: We conducted a double-blind randomized placebo-controlled clinical trial to evaluate the safety, immunogenicity, and effect on viral dynamics of a therapeutic vaccine produced with monocyte-derived dendritic cells (MD-DC) loaded with a high dose of heat-inactivated autologous (HIA) HIV-1 in combination with pegylated interferon alpha 2a (IFNα-2a) in people with chronic HIV-1. Results: Twenty-nine male individuals on successful ART and with CD4+ ≥450 cells/mm3 were randomized 1:1:1:1 to receive three ultrasound-guided inguinal intranodal immunizations, one every 2 weeks: (1) vaccine ~107 MD-DC pulsed with HIA-HIV-1 (1010 HIV RNA copies) (n = 8); (2) vaccine plus three doses of 180 mcg IFNα-2a at weeks 4-6 (n = 6); (3) placebo = saline (n = 7); and (4) placebo plus three doses of 180 mcg IFNα-2a (n = 8). Thereafter, treatment was interrupted (ATI). Vaccines, IFNα-2a, and the administration procedures were safe and well tolerated. All patients' viral load rebounded during the 12-week ATI period. According to groups, changes in viral set-point between pre-ART and during ATI were not significant. When comparing all groups, there was a tendency in changes in viral set-point between the vaccine group vs. vaccine + IFNα-2a group (>0.5log10p = 0.05). HIV-1-specific T-cell responses (IFN-Æ´ Elispot) were higher at baseline in placebo than in the vaccine group (2,259 ± 535 vs. 900 ± 200 SFC/106 PBMC, p = 0.028). A significant difference in the change of specific T-cell responses was only observed at week 4 between vaccine and placebo groups (694 ± 327 vs. 1,718 ± 282 SFC/106 PBMC, p = 0.04). No effect on T-cell responses or changes in viral reservoir were observed after INFα-2a administration. Discussion: Results from this study show that intranodally administered DC therapeutic vaccine in combination with IFNα-2a was safe and well-tolerated but had a minimal impact on viral dynamics in HIV-1 chronic infected participants. Clinical Trial Registration: (www.ClinicalTrials.gov), identifier NCT02767193.

High rate of long-term clinical events after antiretroviral therapy resumption in HIV-positive patients exposed to antiretroviral therapy interruption.

OBJECTIVE: We analyzed the incidence rate of long-term events in patients on antiretroviral therapy (ART) previously exposed to therapy interruption. DESIGN: A single-center cohort study involving participants in ART interruptions (ARTI) clinical trials (n = 10) was conducted. METHODS: Non-AIDS events after ART resumption were analyzed. A control group not exposed to ARTI was randomly selected from the same cohort and a propensity score of belonging to ARTI group was estimated based on age, sex, CD4+ nadir value, time from HIV diagnosis to ARTI, time from HIV diagnosis to starting ART and time of suppressed viral load, and used to adjust effect estimates. RESULTS: One hundred and eighty-one patients were included, 136 in ARTI and 45 in the control arm. Median time of known HIV-1 infection was 21 years and median time from ART resumption to first non-AIDS event was 5.2 years. A significantly higher proportion of patients with ARTI had an event as compared with control group [raw percentages: 43% (n = 53) vs. 23% (n = 10), P = 0.015]. These differences were confirmed when only the non-AIDS events occurring after ART resumption were analyzed [adjusted hazard ratio (aHR) = 2.43, 95% confidence interval (CI) 1.15-5.12]. The logistic model adjusted for the propensity score indicated that patients with an ARTI had a four-fold higher risk of having at least one non-AIDS event (P = 0.002). CONCLUSION: We found a higher risk of having at least one non-AIDS event years after ART resumption in HIV-infected patients exposed to ARTI as compared with controls. These data should be taken into consideration for future functional cure clinical trials.

Feasibility of using monocyte-derived dendritic cells obtained from cryopreserved cells for DC-based vaccines.

The study of the effect of cryopreservation on the functionality of monocyte-derived dendritic cells (MDDCs) and dendritic cells (DCs) is essential for their use in different clinical applications such as DCs-based vaccines. Its full maturation and its optimal functionality are crucial for DCs based immunotherapy. In this study, we compared MDDCs derived from fresh and cryopreserved PBMCs in the aspects of phenotype and its effect on T cells at the level of proliferation and cytokine secretion. We pulsed MDDCs obtained from fresh and cryopreserved PBMCs with two different stimuli, CEF and SEA, and the expression maturation markers and cytokine secretion were analyzed. Our results showed that the cryopreservation had no effects in the phenotype of the MDDCs obtained, cell viability, maturation markers expression and/or cytokines secretion, independently whether MDDCs had been generated from fresh or cryopreserved PBMCs. Thus, this study suggests that the use of cryopreserved cells is a good method to keep the cells before use in immunotherapy, avoiding the variability within same individual due to severe blood draws. Even so, the interpretation and comparison of different results should be done considering the different cryopreservation techniques and assays, and their effects on PBMCs, specifically on MDDC and DC cells.

Enhancement of the HIV-1-Specific Immune Response Induced by an mRNA Vaccine through Boosting with a Poxvirus MVA Vector Expressing the Same Antigen.

Development of a vaccine against HIV remains a major target goal in the field. The recent success of mRNA vaccines against the coronavirus SARS-CoV-2 is pointing out a new era of vaccine designs against pathogens. Here, we have generated two types of mRNA vaccine candidates against HIV-1; one based on unmodified vectors and the other on 1-methyl-3'-pseudouridylyl modified vectors expressing a T cell multiepitopic construct including protective conserved epitopes from HIV-1 Gag, Pol and Nef proteins (referred to as RNA-TMEP and RNA-TMEPmod, respectively) and defined their biological and immunological properties in cultured cells and in mice. In cultured cells, both mRNA vectors expressed the corresponding protein, with higher levels observed in the unmodified mRNA, leading to activated macrophages with differential induction of innate immune molecules. In mice, intranodal administration of the mRNAs induced the activation of specific T cell (CD4 and CD8) responses, and the levels were markedly enhanced after a booster immunization with the poxvirus vector MVA-TMEP expressing the same antigen. This immune activation was maintained even three months later. These findings revealed a potent combined immunization regimen able to enhance the HIV-1-specific immune responses induced by an mRNA vaccine that might be applicable to human vaccination programs with mRNA and MVA vectors.

Association of Transcriptomic Signatures of Inflammatory Response with Viral Control after Dendritic Cell-Based Therapeutic Vaccination in HIV-1 Infected Individuals.

Systems vaccinology has seldomly been used in therapeutic HIV-1 vaccine research. Our aim was to identify early gene 'signatures' that predicted virus load control after analytical therapy interruption (ATI) in participants of a dendritic cell-based HIV-1 vaccine trial (DCV2). mRNA and miRNA were extracted from frozen post-vaccination PBMC samples; gene expression was determined by microarray method. In gene set enrichment analysis, responders showed an up-regulation of 14 gene sets (TNF-alpha/NFkB pathway, inflammatory response, the complement system, Il6 and Il2 JAK-STAT signaling, among others) and a down-regulation of 7 gene sets (such as E2F targets or interferon alpha response). The expression of genes regulated by three (miR-223-3p, miR-1183 and miR-8063) of the 9 differentially expressed miRNAs was significantly down-regulated in responders. The deregulation of certain gene sets related to inflammatory processes seems fundamental for viral control, and certain miRNAs may be important in fine-tuning these processes.

Impact of Transcriptome and Gut Microbiome on the Response of HIV-1 Infected Individuals to a Dendritic Cell-Based HIV Therapeutic Vaccine.

Therapeutic vaccines based on dendritic cells offer a good approach to HIV-specific T-cell responses and partial control of the viral load after antiretroviral therapy interruption. The aim of the present study was to identify mRNA expression profiles and to assess the impact of the gut microbiome composition for predicting the viral load control after antiretroviral therapy interruption. We enrolled 29 patients to receive either placebo or a monocyte-derived dendritic cell vaccine. Patients with a decrease in their viral load of >0.5 log10 copies/mL by 12 weeks after antiretroviral therapy interruption were considered responders. In total, 66 genes were considered differentially expressed between responders and non-responders. Enrichment analysis revealed several upregulated pathways involved in the host defense response to a virus via the type I interferon signaling pathway. Regarding the gut microbiota, responders showed enriched levels of Bacteroidetes (p < 0.005) and Verrucomicrobia (p = 0.017), while non-responders were enriched with Tenericutes (p = 0.049) and Actinobacteria (p < 0.005). We also found important differences at the genus level. However, we did not discover any effect of the dendritic cell vaccine on the transcriptome or the gut microbiota. An alternative analysis did characterize that the microbiota from responders were associated with the metabolic production of short-chain fatty acids, which are key metabolites in the regulation of intestinal homeostasis. The evidence now consistently shows that short-chain fatty acid depletion occurs in HIV-infected individuals receiving antiretroviral treatment.

In the Era of mRNA Vaccines, Is There Any Hope for HIV Functional Cure?

Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure.

High rates of long-term progression in HIV-1-positive elite controllers.

INTRODUCTION: Elite controllers (EC) are a rare group of HIV-1-positive individuals who suppress viral loads (VL) to undetectable levels with elevated CD4 T-cell counts in the absence of ART. While rates of short- and mid-term progression have been described in these patients, few studies have focused on their long-term outcome This study aims to describe the virological and immunological behaviour in a cohort of elite controllers followed up for a median of 17 years in the University Hospital, and to identify factors that may be related to disease progression. METHODS: We conducted a descriptive, prospective and single-centre study of all HIV-positive adults recorded in the University Hospital database who met the definition criteria for EC. EC were defined as patients having two consecutive undetectable VL without ART for at least one year. Patients were followed from baseline up to December 2019, to the development of a progression event (loss of VL control, CD4+ T cell decline, AIDS or death) or to the censoring date (lost to follow-up or initiation of ART). Predictive models of progression were calculated. RESULTS: Fifty-nine EC were identified with a median follow-up of 17 years contributing 1033 PYFU. The median (95% CI) time duration from HIV-1 diagnosis to disease progression was four (1.7 to 6.3) years. Forty-nine (83%) presented progression to the composite end-point, 44 (74.6%) lost viral control, 39 (66.1%) lost immunological control, two developed AIDS and two died. Only 10 patients (16.9%) did not show progression of any kind. Independent predictors of virological progression were sexual risk of HIV-1 acquisition and VL blips during the first year of follow-up (baseline). The only independent predictor detected for progression to a composite end-point was VL blips during the first year of follow-up (baseline). CONCLUSIONS: The rate of long-term progression in EC was very high. Only a minority of patients did not show clinical progression after a median of 17 years of follow-up. These results should be taken in account when considering EC as a model of HIV-1 remission.

Off the beaten path: Novel mRNA-nanoformulations for therapeutic vaccination against HIV.

Over the last few years, immunotherapy for HIV in general and therapeutic vaccination in particular, has received a tremendous boost, both in preclinical research and in clinical applications. This interest is based on the evidence that the immune system plays a crucial role in controlling HIV infection, as shown for long-term non-progressors and elite controllers, and that immune responses can be manipulated towards targeting conserved epitopes. So far, the most successful approach has been vaccination with autologous dendritic cells (DCs) loaded ex vivo with antigens and activation signals. Although this approach offers much promise, it also comes with significant drawbacks such as the requirement of a specialized infrastructure and expertise, as well as major challenges for logistics and storage, making it extremely time consuming and costly. Therefore, methods are being developed to avoid the use of ex vivo generated, autologous DCs. One of these methods is based on mRNA for therapeutic vaccination. mRNA has proven to be a very promising vaccine platform, as the coding information for any desired protein, including antigens and activation signals, can be generated in a very short period of time, showing promise both as an off-the-shelf therapy and as a personalized approach. However, an important drawback of this approach is the short half-life of native mRNA, due to the presence of ambient RNases. In addition, proper immunization requires that the antigens are expressed, processed and presented at the right immunological site (e.g. the lymphoid tissues). An ambivalent aspect of mRNA as a vaccine is its capacity to induce type I interferons, which can have beneficial adjuvant effects, but also deleterious effects on mRNA stability and translation. Thus, proper formulation of the mRNA is crucially important. Many approaches for RNA formulation have already been tested, with mixed success. In this review we discuss the state-of-the-art and future trends for mRNA-nanoparticle formulations for HIV vaccination, both in the prophylactic and in the therapeutic setting.

Prolonged administration of maraviroc reactivates latent HIV in vivo but it does not prevent antiretroviral-free viral rebound.

Human immunodeficiency virus (HIV) remains incurable due to latent viral reservoirs established in non-activated CD4 T cells that cannot be eliminated via antiretroviral therapy. Current efforts to cure HIV are focused on identifying drugs that will induce viral gene expression in latently infected cells, commonly known as latency reversing agents (LRAs). Some drugs have been shown to reactivate latent HIV but do not cause a reduction in reservoir size. Therefore, finding new LRAs or new combinations or increasing the round of stimulations is needed to cure HIV. However, the effects of these drugs on viral rebound after prolonged treatment have not been evaluated. In a previous clinical trial, antiretroviral therapy intensification with maraviroc for 48 weeks caused an increase in residual viremia and episomal two LTR-DNA circles suggesting that maraviroc could reactivate latent HIV. We amended the initial clinical trial to explore additional virologic parameters in stored samples and to evaluate the time to viral rebound during analytical treatment interruption in three patients. Maraviroc induced an increase in cell-associated HIV RNA during the administration of the drug. However, there was a rapid rebound of viremia after antiretroviral therapy discontinuation. HIV-specific T cell response was slightly enhanced. These results show that maraviroc can reactivate latent HIV in vivo but further studies are required to efficiently reduce the reservoir size.

Immunological and virological efficacy of different antiretroviral regimens initiated during acute/recent HIV infection.

OBJECTIVES: Antiretroviral treatment (ART) during acute/recent HIV infection decreases transmission and optimizes immune recovery but the optimal ART-regimen in this setting is unknown. The objectives were to analyze the virological efficacy, immunological reconstitution and tolerability of different ART-regimens at 3 years after starting ART during acute/recent HIV infection. DESIGN: Retrospective cohort study of consecutive acutely/recently infected patients who started ART within 6 months postinfection. METHODS: We compared regimens based on protease-inhibitors (N = 28), integrase-strand-transfer-inhibitors (InSTI, N = 87) and nonnucleoside-reverse-transcriptase-inhibitors (N = 22). Virological suppression (viral load <50 copies/ml), immune reconstitution (CD4 T-cell count >900 cells/µl and CD4/CD8 ratio >1) and adverse events leading to ART discontinuation at 1 and 3 years were compared. RESULTS: Baseline characteristics were comparable among groups. Overall viral suppression at 1 (96%) and 3 years (99%) was comparable in all ART regimens and, InSTI group, comparable for dolutegravir and elvitegravir within InSTIs. CD4 T-cell counts at 1 year were comparable in all ART regimens. Overall proportion of patients reaching CD4 cell count more than 900 cells/µl and CD4/CD8 ratio more than 1 was 36% and 40% and 46% and 63% at 1 and 3 years, respectively with no differences among ART regimens. Starting ART during the earliest Fiebig stages (I-V vs. VI) was associated with higher rates of CD4 cell count more than 900 cells/µl at 3 years (P = 0.027). Discontinuation due to adverse events was more frequent with nonnucleoside-reverse-transcriptase-inhibitors compared with other ART classes. CONCLUSION: Viral suppression and immunological recovery were excellent, with no differences between ART regimens. Earlier ART initiation was associated with a higher proportion of long-term immunological recovery.